Lively looked lovely in a shimmery, body-hugging gown, which she styled with statement rings and strappy silver sandals.
The blond beauty, who is at the annual film festival to promote her new film, Café Society, was all smiles while posing next to the film's director and writer, Woody Allen, and her co-star, Corey Stall, who appeared to be ecstatic about seeing Lively's growing belly in person.
Kristen Stewart, who also stars in Café Society, hit the red carpet in a much less glitzier number. Stewart opted for a sheer black blouse with pockets that perfectly covered her breasts. She paired the revealing top with a long skirt and black stilettos.
Longoria's pal, Victoria Beckham, hit the red carpet in a chic black-and-white bustier and high-waisted black trouser combo, two pieces from her fall/winter 2016 fashion collection. She accessorized with a sparkly bracelet and pointy-toe heels.
Before arriving, Beckham took to Instagram to share some snaps of her getting ready for the evening.
She also shared a Snapchat video of herself with Longoria and their hair stylist, Ken Paves, using the app's bunny filter. (We're glad to see Beckham's finally mastered it!)
Bella Hadid went with a flashier look, rocking a Cavalli Couture mermaid dress made of silk tulle and embroidered with crystals. She completed the head-turning ensemble with a glitzy statement necklace.
Taking a style cue from Beckham, Susan Sarandon also rocked a black-and-white outfit to the star-studded ceremony. She looked as hip as ever while sporting sunglasses as she posed for photographers on the red carpet with Julianne Moore and Naomi Watts.